In organs generally, it is conventional to actuate a number of tones upon depressing a given key. In many types of electrical organs, electrical tone generators may be keyed by means of an electrical switch connected between the tone generator and a source of direct current potential, the switch being actuated in response to depressing of one of the keys of the keyboard of the musical instrument. U.S. Pat. No. 3,617,603 of Nov. 2, 1971, entitled "CHIFF CIRCUITS FOR ELECTRONIC ORGANS" of Wayne and Meyer, and U.S. Pat. No. 3,660,587 of May 2, 1972, entitled "ELECTRONIC ORGAN KEYING CIRCUITS" of Martin disclose an electrical organ in which a single pole single throw key switch activates two photoelectric tone sources, corresponding, for example, to a main tone component and a chiff tone component of the organ tone through two parallel envelope circuits. As more fully described hereinafter, FIG. 1 illustrates such a system.
U.S. Pat. No. 3,390,223 to Wayne discloses an electrical organ in which certain pipe organ simulated tones decay at a pitch which is flat with respect to the steady-state pitch. In the organ of the Wayne patent, however, this is accomplished by driving, at the steady-state pitch, a resonant circuit which is tuned flat with respect to the steady-state pitch, so that when the key switch is opened and the driving signal terminates, the resonant circuit produces a decaying electrical signal at the resonant frequency of the circuit which is flat with respect to the steady-state pitch.
U.S. Pat. No. 3,037,413 to Markowitz entitled "ELECTRIC ORGAN WITH TRANSIENT SPEECH EFFECTS" is also an example of an electrical organ in which a single key is utilized to excite a plurality of tone sources through separate keying circuits connected in parallel with the keying circuit of the principal tone.